Well logging



Sept. 25, 1951 B. w. SEWELL 2,559,390

WELL LOGGING Filed Aug. 20, 1946 2 Sheets-Sheet l M00 FZOWdoMMuTA'ro'zz.

PO WER acneopa B. w. SEWELL 2,569,390

WELL LOGGING 2 Sheets-Sheet 2 Sept. 25, 1951 Filed Aug. 20, 1946Patented Sept. 25,1951

WELL LOGGING Benjamin W. Sewell, Tulsa, Okla., assignor to Standard OilDevelopment Company, a corporation of Delaware Application August 20,1946, Serial No. 691,850

3 Claims. 1

The present invention is directed to a method and apparatus for loggingwells while drilling.

The principal object of the present invention is the provision of anapparatus and method for logging wells while drilling.

An additional object of the present invention is to provide in anapparatus of the aforesaid type an arrangement whereby electricalconductors may be lowered in the drill stem without twisting due torotation of the drill stem.

A further object is to provide in an apparatus of the aforesaid typenovel means for making contact between an isolated conductive sectionnear the drill bit and a conductor lowered through the drill stem so asto utilize said section as an electrode.

Another object of the present invention is the provision of a method andapparatus of the aforesaid type with which any type of logging requiringthe use of electrical conductors, such as conductivity measurements orradioactivity measurements or the like, may be carried out duringdrilling.

Still another object of the present invention is the provision of anovel means and method type in which the probing means may be housed inthe kelly of a drill stem during drilling and used intermittently, asdesired, for logging purposes.

Yet another object of the present invention is th provis on of a novelmeans and method for taking a signal oif a conductor carried inside arotating drill stem.

Other objects and advantages of the present invention will appear fromthe accompanying drawing in which,

Fig. 1 is a front elevation of the up er part of a drill stem embodvingpart of the apparatus of the present invention:

Fig. 2 is a vertical section through the lower portion of the same drillstem embod ing the remainder of the apparatus of the present invention;and

Fig. 3 is a vertical section showing a modified wall construction forthe lower part of the drill stem.

Referring to the drawing in detail, numeral I designates a bore hole inwhich is arranged. a drill stem 2, the upper end of which isconnected inthe usual manner to a key 3. Bet een the kelly and the swivel joint 4 isarranged a conduit 5 having separated arms 5 which, in the embodimentshown. assume the form of a rectangle, the conduit 5 being connected atits upper 2 end to the swivel and at its lower end to the kelly.

sections 24 constitutes an electrode.

Suitably fixed to each of the arms 6 at a mid point thereof is a bearing1 in which is journaled the shaft 8 of a reel 9 on which is wound acable I0 carrying one or more conductors. The inner end of eachconductor is connected in the usual manner with a slip ring ll fixed tothe shaft 8 on which is carried the usual spring contact member l2electrically connected to another slip ring or commutator I3 mounted onthe upper end of conduit 5 and suitably insulated therefrom by aninsulating sleeve [4 mounted thereon. To frictionally engage slip ringI3 is a second spring contact l5 connected to recorder l6 which, as iscommon in well-logging equipment, contains a source of power to supplythe probes or electrodes.

The reel 9 is driven by a motor 1! rigidly suspended from the arms 6 bysuitable brackets l8 so as to rotate with the arms as a unit and gearedto shaft 8 by a suitable gearing 19. To supply power to the motor, theupper end of conduit 5 carries suitable slip rings or commutators 2%!connected to a source of power by leads 2! and .the upper part of theconduit 5, passes through the arms 6, the lower part of the conduit 5,and

the kelly 3, into the drill stem 2. Leakage of mud or drilling fluid tothe outside around the cable is prevented by suitable packing. suspendedfrom the cable is an electrode assembly composed of alternate sectionsof metal tubing 24 and tubing of insulated material, such as Bakelite25. .In the embodiment shown, the sheath of the cable is anchored in theupper metal section 24 in the manner well known in devices of this type.Each of the other metal Mounted on each electrode is an assembly ofspring arms 7 26 having their ends connected to suitable collars .2! and28. One of these collars is fixed to the tube 24 and the other isslidable thereon. Where two electrodes are employed and two conductors,each of the conductors is connected to the interior of one of thetubular members 24 so as to provide electrical contact between saidtubular member and the recording apparatus at the surface as well aswith the source of power at the surface.

lhe lower end of the drill stem is likewise made up of conductive andinsulating sections corresponding in number and spacing to those on theelectrode assembly. In the embodiment shown, there are two insulatingsections 29 and two conductive sections 30, the lower one of whichcarries the drill bit 32. These insulating sections may be fabricated inany desired manner but in order to impart strength to the assembly towithstand the torque of drilling, a suitable construction for 1 theseinsulating sections is shown in Fig. 3. In this construction, each metalsection 30 has a thinner extension 3| on its end. These thinnerextensions are arranged so as to be concentric with each other and havea different diameter so that an annular space is formed between them.Insulating material is molded into place around these extensions in themanner shown so as to form a continuous inner and outer surface with themetal sections 3! to produce, in effect, an integral structure. Theseinsulating sections have high shearing strengths, and, together with theextensions 3 l, are able to withstand the torque and other stressesimposed upon the assembly during the drilling operation.

The spring arms ZS are suiiiciently bowed so that when the electrodeassembly is in the drilling stem, these arms make goodf'rictionalcontact with their adjacent metal sections 30. The conductorscarried by the cable being directly connected to the metal sections 24,there is provided a complete electric circuit, including the electrodes,the earth between the electrodes, the conductors, and the recorder. Itwill be understood that in conventional electric logging the source ofpower for passing current through the earth formations is included inthe recorder unit. It will be apparent,'of course, that if a differentsource of power is required, it will be connected 40 to the commutator[3. Where it is desired only ment shown will occur to those skilled inthe art.

Such modifications are embraced within the scope of the presentinvention in so far as they embody the principles underlying the presentinvention. It will be observed that the arrangement shown makes possiblethe transmission of electric signals between a point in the bore holeand the surface while drilling without incurring the difficulty oftwisting of the transmission cable about its axis.

The nature and objects of the present invention having thus been setforth and a specific*- illustrative embodiment of the same given, whatis claimed and desired to be secured by Letters Patent is:

1. In an apparatus for the rotary drilling and simultaneous logging of abore hole, a rotatable drill stem, a head on said drill stem comprisinga pair of spaced hollow arms in fluid communication with the interior ofsaid drill stem, a reel journaled in said arms with its longitudinalaxis 7 perpendicular to the longitudinal axis of said drill stem, acable wound on said reel, signal producing means carried by said cable,signal conducting means carried by said cable, signal receiving meansmounted on said drill stem for rotation therewith and independent ofsaid reel, signal transmitting means connecting said signal conductingmeans with said signal receiving means and means for taking off a signalfrom said conducting means.

2. An apparatus for drilling a well by the rotary method andsimultaneously logging it comprising a hollow drill stem mounted forrotation, at least one electrically conductive section arranged adjacentthe lower end of said drill stem and insulated therefrom, an elongatedprobing device having at least one conductive section, spring contactingmeans carried by said probing device adapted to make electrical contactbetween the electrically conductive section thereof and the electricallyconductive section of said drill stem, a cable carryingv said probingdevice, at least one conductor in said cable connected to anelectrically conductive section of said probing device, a reel mountedon the upper end of said drill stem for carrying said cable, said reelbeing mounted for rotation about its transverse axis with said drillstem and for rotation about its longitudinal axis, the longitudinal axisof said reel being disposed in perpendicular relation to thelongitudinal axis of the drill pipe, at least one slip ring carried bysaid reel and connected to one of said conductors, at least one slipring carried by said drill stem and rotatable therewith, an electricalconnection between said reel slip ring and said drill stem slip ring anda recorder at the surface electrically connected to said drill stem slipring.

3. An apparatus for drilling a bore hole by the rotary method andsimultaneously logging it which comprises a hollow drill stem mountedfor rotation, a head carried b said drill stem comprising spaced hollowarms in fluid connection with said drill stem, a swivel connectionbetween said head and a conduit for supplying a fluid medium to saiddrill stem, a reel journaled in said arms with its longitudinal axisvertical to the longitudinal axis of said drill stem whereby said reelis capable of rotation about its transverse axis with said drill stemand of rotation about its longitudinal axis, means for rotating saidreel about its longitudinal axis, an electrical recorder adapted'to bearranged at the surface, sliding electrical contacts between saidrecorder and said reel, a cable carrying an electrical conductor woundon said reel, a probing device carried by the free end of said cable,said conductor being connected to said probing device and said slidingconnections, and means at the. upper end of said drill stem for passingsaid cable into said drill stem.

BENJAMIN W. SEWELL.

REFERENCES orrsn The following references areof record in the file ofthis patent:

UNITED STATES PATENTS

